Okay but why should anyone else care? Perversion strikes me as an argument rooted in either personal taste or Bronze Age scripture.
Alright, let's have a bit of real talk about "perversion". Let's go ahead and set aside the figurative framing wrapped up in prudery about exposed ankles and crap like that, and address paraphilia.
I'm assuming that you, like pretty much every other college kid out there, took the basic psych 101 class, in which they discuss sexual deviance? Yeah, that's where paraphilias are. Paraphilias are essentially sexual addictions. They're a sexual fascination with something that is not associated with the normal modes of sexual reproduction. Someone uber puritan out there might want to lump oral sex into that, but pretty much as long as we've had any records of sexual behavior, oral sex has been in the mix and very common.
Some paraphilias are fairly benign in the grand scheme - having a foot fetish, for example, is unlikely to cause problems to anyone else. At worst, it might make it really challenging for the person with that paraphilia to find a partner, or it could hamper their ability to have a healthy sexual relationship, one where both parties gain pleasure and satisfaction in a mutually beneficial and respectful way. Others, like pedophila, are quite malign. They represent a risk to innocent minors.
People with paraphilias, like addicts, tend to seek gratification of their addiction. They seek out a means to attain sexual satisfaction related to their paraphilia. A pedophile seeks to be around kids, even if they're not actively looking to abuse them. They seek out sexualized imagery of kids, they fantasize about sexual acts with children. The same thing holds for any other paraphilia - including bondage, sadism, masochism, foot fetishes,
and transvestism.
And just like addictions, the more you feed the paraphilia, the stronger it becomes. You can't conquer an opioid addiction by giving people ever increasing amounts of oxy - there is no amount that is "enough" to satisfy the addiction. In some cases, a person can manage their addiction to a degree - you get "functional" alcoholics and heroin addicts, who can maintain their lives with more or less the same amount of booze or horse to get by. But it's not a happy place, it's just endurance. And that maintenance level frequently ends up being right about the maximum amount that can be used without permanent harm, it's essentially the saturation level. So the more a pedophile spends time around kids, the stronger their pedophilia becomes. Some might be able to find a balance of sorts, where they get enough exposure to get by without actually harming a kid, but it's always an uneasy balance. Similarly, transvestites might find balance if they have a means to get just enough cross-dressing titillation, but there's always a hunger for a bit more.
More than that, however, is that paraphilias cluster and propagate in a way analogous to addictions. A person with one drug addiction is at materially increased risk of developing a second (or third or fourth... ) addiction. Some people might have a "favorite" drug, but the reality is that a drug addict is likely to use more drugs of more types. They cluster and multiply. The same thing is true of paraphilias - if a person has one paraphilia, they're at significantly higher risk of developing another paraphilia.
Drug addicts have a tendency to escalate into theft, robbery, mugging, and other criminal behavior. They have a tendency to lose jobs, and become homeless. Paraphiliacs have a tendency to escalate too - voyeurism and exhibitionism are some of the more common paraphilias, and they're correlated with increased risk of sexual offending - stalking, harassment, sexual assault, rape. There's a disproportionate prevalence of paraphilias among serial killers and serial rapists than among the general population. Transvestism is far overrepresented among serial killers, for instance.
Not every paraphiliac is a risk to others, just like not every alcoholic is a risk to others. But just like with alcohol, they absolutely represent an increased risk. And the more extreme the paraphilia, the higher the risk.
A person who openly engages in cross-dressing and "age play" in public is indicative of a higher risk of sexual predation to those around them. That's why other people care about "perversion".